goto bugs, wait-for automatically, logging, throwing, and more

[joelgriffith]

Lots of cleanup and updates to docs. Here's the high-level:

• goto throws on network failures (redirects are considered OK)
• Most DOM methods (click, type, exists...) now default to "waiting" for the respective selectors to appear before executing.
• First stab at also waiting for pageloads to hapen before the next "action".
• Most API's now throw if something is remotely odd (elements not there, IE) and return values

Still need to do changelog